The invention discloses a flow field visual measurement experimental device based on matched index of refraction. The device comprises a main loop system, a first cooling loop system, a second coolingloop system and a bypass branch. The bypass branch divides the main loop system into a first part and a second part, the first cooling system is located at the first part, the second cooling loop system is located at the second part, and the first part includes a liquid tank, a conventional centrifugal main pump and a main heat exchanger, the first cooling system also includes a main heat exchanger, the first cooling system takes away the heat generated by working of the conventional centrifugal main pump on fluid through the main heat exchanger so as to control the temperature of the main loop system, the second part includes an electromagnetic flowmeter and a test section, the second cooling loop system is set between the electromagnetic flowmeter and the test section, and the second cooling loop system is set for controlling the fluid temperature of the test section, and the bypass branch regulates the flow passing through the test section.